Unconventional looms, particularly those adapted for pneumatic or hydraulic weft insertion in which the weft length is prepared for each successive weft insertion, are provided with a device for weft cutting mounted at the input side of the machine, from the viewpoint of weft insertion.
Devices are known for cutting weft. These devices can be classified according to their construction and the time at which cutting actually takes place, i.e., before interlacing or after interlacing the inserted weft. A particular requirement is imposed on weft cutting when weaving with two or more wefts. In this case, in addition to a device for preparing the weft and inserting it, a device for controlling weft is required. The controlling device cooperates closely with the cutting device because, before the actual cutting, it is necessary to locate the inserted wefts from the separate nozzles in a predetermined sector corresponding to the position of the weft and the opening of the knife blades.
One of the weft cutting devices hitherto known is a device in which the weft is inserted into a shed from an outer weft supply bobbin. The device is controlled synchronously with the movement of the weft-inserting elements, and includes two mutually oppositely movably guided cutting jaws, of which each is provided with a blade. One of the blades is disposed on the edge of an entrapping dent in one of the cutting jaws. The entrapping dent is shielded from the shed and is opened towards the direction of weft insertion. The blades are positioned in a plane parallel to the direction of weft insertion.
Disadvantages of this known device include the difficulty of forming a shaped blade in one of the cutting jaws, and in the impossibility of using the whole length of the blade for cutting. The positioning of the blade in a plane parallel to the direction of weft insertion is also disadvantageous.